This invention relates to the field of modular joints and connectors, and in particular, to the joinder of elongated rod elements with flexible, universally-configurable joints in a manner that ensures tensile integrity.
Modular elongated elements such as rods, tubes, poles, pipes, struts and the like are often joined together into more complicated constructs, using a wide variety of joints between adjacent such modular elongated elements. In some situations, it is desired to connect a plurality of these modular elongated elements end to end so as to create a longer elongated construct, for example, elongated poles used to pitch a tent. In other situations, it is desired to join two or more such modular elongated elements at a vertex in such a way that the vertex angle formed between adjacent modular elongated elements is other than 180 degrees (i.e., the elements are not end to end), and is flexible over a continuous range of angles and not fixed to any predetermined angle. This is useful in a wide range of construction and framing applications, and also for toys and educational demonstrations. For example, the joining of modular elongated elements is frequently used to model various polyhedral constructs illustrating mathematical and scientific concepts.
The problem is that virtually all devices and methods known in the art for joining modular elongated elements utilize complex joints which are frequently limited because they impose fixed, predetermined angles between adjacent modular elongated elements, and / or because they limit the number of modular elongated elements that can be joined together at any given vertex to a specific predetermined number, or to a specific maximum number, and / or because these joints are made only through a complicated and time-consuming series of interconnections steps, and / or because the resulting constructs do not possess sufficient structural integrity to hold together well under stresses applied to them. Additionally, many joints are typically fairly complex elements in and of themselves, requiring various tools for assembly.
For example, U.S. Pat. No. 3,830,011 restricts the number of struts, and relative angles of struts, which may be joined any given vertex because of the various connector pieces such as are shown in FIGS. 21 through 32. U.S. Pat. No. 3,998,003 similarly restricts strut numbers and angles at a vertex by the structure of the linking members (12) therein. The same limitations are imposed by the linkages used in, for example, U.S. Pat. Nos. 4,819,402; 5,116,193; 5,430,989; 5,690,446; and 6,146,050.
While U.S. Pat. No. 5,785,529 does not appear to restrict the numbers and angles of rods that can be connected at a given vertex, it does not provide any tensile or other structural integrity for the constructs that it is used to form, since the rods (12) are easily pulled out from the connectors (10). Additionally, it appears that over time, with enough puncturing, connectors (10) will become degraded and need to be replaced.
The rod tying apparatus in U.S. Pat. No. 5,365,715 exemplifies an extremely complicated system of rod interconnection, and is certainly not desirable or applicable to a broad range of circumstances.
Tensile integrity constructs, and / or constructs utilizing flexible connectors, are a preferred way to provide structural integrity and well as, in some instances, flexibility insofar as the numbers and angles of rods that can be interconnected at a given vertex. Even here, however, the prior art contains serious limitations.
U.S. Pat. No. 3,422,565, for example, uses tubes, plugs and resilient links. However, the insertion of plugs into the tubes, and the connection of the resilient links to the plugs, is rather complex. Further, the links themselves are complex, as can be observed from the transverse slicing (18) and joining (21) shown in FIGS. 4 and 5 and described in column 2, lines 37 55. Depending on the particular structure and orientation of adjacent rods, tensile integrity may also be lacking, as it depends in part on the plugs (12) remaining firmly within the tubes (11), and thus on the frictional forces between the plugs (12) and tubes (11).
U.S. Pat. No. 4,731,962 also involves a complex linking process, and is unsightly insofar as the tensile cords (15) are outside of the rods. This invention does not appear to lend itself well to connecting rods end-to-end with tensile integrity, or to universally assembling polyhedral and other shapes and frames in general.
U.S. Pat. No. 4,404,240 uses various threads (6,8) in various configurations for interconnection, resulting in a complex, non-universal connection process, also without tensile integrity. The threading of these interconnections is also rather tedious and complicated. U.S. Pat. No. 4,614,502 uses strings (14) and pins (13) a manner also requiring complex and tedious threading to interconnect adjacent elements. Finally, U.S. Pat. No. 4,583,956 uses tendons (11) which are also strings threaded in a complex and tedious manner.
None of these references provides an optimal combination of universality, tensile integrity, modularity, and ease of assembly.
It is therefore desirable to provide modular elongated elements that can be connected with other similar modular elongated elements at any desired vertex angle, rather than at fixed, predetermined angles.
It is further desirable to provide modular elongated elements that can be connected with other similar modular elongated elements without limitation as to the number of such modular elongated elements that can be connected together at any given vertex.
It is further desirable to provide modular elongated elements that can be interconnected easily and quickly, without any tools.
It is further desirable to provide modular elongated elements that, once connected, provide inherent tensile integrity to the constructs they form.
It is further desirable to provide modular elongated elements that are universal, i.e., that provide suitable building blocks to construct virtually any construct such as a structure, assembly, frame, polyhedron, elongated composite (e.g. pole), or other elongated-element-based construct that is desired.
A modular elongated element, an intramodule tensile device, a pair of securing and linking devices, and an intermodule connector device, interconnected using the devices and methods disclosed herein, are used to construct a virtually limitless variety of inherently-tensile constructs. In the most elemental module, the intramodule tensile device connects a pair of securing and linking devices which are in turn secured to two ends of the modular elongated element.